Application method, applicator, optical member, and optical device

ABSTRACT

An applicator including a liquid discharge head for discharging a treatment liquid in droplet form, and a discharge control device for controlling the discharge of droplets from the liquid discharge head. The discharge control device divides a surface of a member into a plurality of regions according to the shape of the surface, and controls the application quantity for each region.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional patent application of U.S. Ser. No.10/630,354 filed Jul. 30, 2003 and claims priority to Japanese PatentApplication Nos. 2002-226069 filed Aug. 2, 2002 and JP 2003-198657 filedJul. 17, 2003, all of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a method of application and anapplicator, and particularly to a technique for applying a treatmentliquid onto a surface of a member such as an optical member.

BACKGROUND OF THE INVENTION

Surfaces of plastic eyeglass lenses and other optical lenses aregenerally subjected to treatments for enhancing their performance andfunctions. Examples of such treatments include a primer coating, a hardcoating, a dyeing treatment, and an antireflection treatment.

Primer coatings give an optical lens the function of enhancing theadhesion between the optical lens substrate and a hard coating film, andimprove impact resistance. For plastic eyeglass lenses, techniques havewidely been used in which a primer liquid is applied onto a surface ofthe plastic eyeglass lens and is then heated to cure the primer. Animmersion method has mainly been used, conventionally, for thistechnique. In this immersion method, a plastic eyeglass lens is immersedin a primer liquid and allowed to stand while being held by a jig. Thelens is then pulled out from the liquid to form a primer film.

Hard coatings give an optical lens many functions, such as enhancing thedurability of an optical lens surface, the adhesion between the lenssurface and a deposition film, and the stability of dyeing properties.For plastic eyeglass lenses, techniques have widely been used in which ahard coat liquid is applied onto a surface of a plastic eyeglass lensand is then heated to cure the hard coat liquid. An immersion method anda spin coating method have mainly been used for this technique,conventionally. In the immersion method, a plastic eyeglass lens isimmersed in a hard coat liquid and allowed to stand while being held bya jig, and is then pulled out from the liquid to form a hard coat film.In the spin coating method, a hard coat liquid is discharged onto asurface of a plastic eyeglass lens and followed by rotating at a highspeed. Thus, a hard coat film is formed.

A dyeing treatment is used particularly in manufacturing process ofplastic eyeglass lenses for giving lenses fashionability. In thistreatment, various colors are dyed, and an immersion method hasconventionally been used. In the immersion method, a plastic eyeglasslens is immersed in hot water in which dye particles are dispersed witha surfactant and is then pulled up.

An antireflection treatment is used to prevent reflection at opticallens surfaces. Surface reflection reduces the transmittance of opticalsystems and increases light not involved in image formation, thusdegrading image contrast. An antireflection treatment therefore,provides wearers with good visibility. Antireflection films haveconventionally been formed in a single layer or a multilayer by vacuumdeposition. A curable liquid having antireflection characteristics hasrecently been devised.

Application methods such as ink jetting or spraying have been devisedfor coating techniques in which a treatment liquid is applied onto onlya desired region of optical lenses. In ink jetting and spraying methods,droplets of a treatment liquid are discharged from a small nozzle. Anapparatus using ink jetting or spraying is reduced in size and can applya treatment liquid at a low electric power. In addition, the liquid canbe used with a high efficiency and production costs can be reduced.Furthermore, these methods are expected to reduce the amounts of usedsolvents and wastes, which promotes environmental protection.

Application, however, of the curable liquid having antireflectioncharacteristics requires precise and uniform control of film thicknessin order to ensure high performance. In an immersion method, thethickness of the coating film decreases at the upper side of the opticalmember and increases at the lower side due to gravity. Also, in the spincoating method, the thickness of a coating film decreases at therotation center of the optical member and increases at the outer regiondue to centrifugal force.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages, an object of the presentinvention is to provide an application method through which a uniformcoating film can be applied onto a member by using a treatment liquidwith an increased efficiency. Another object is to provide an applicatorrealizing the method.

Yet another object of the present invention is to provide an opticalmember having high performance, wherein its functions are enhanced by asurface treatment, and an optical device having the optical member. Inthe method, the treatment liquid is applied in droplet form onto thesurface of the member. The surface is divided into a plurality ofregions according to the shape of the surface, and an applicationquantity is controlled for each of the regions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an applicator according to an embodimentof the present invention;

FIG. 2 schematically shows an application method and an applicatoraccording to the present invention, and (a) is a side view and (b) is aplan view;

FIG. 3 schematically shows another form of an application method and anapplicator according to the present invention, and (a) is a side viewand (b) is a plan view;

FIG. 4 is a schematic representation in which a treatment liquid isapplied onto a curved surface of a member while the number ofapplications is varied from one region to another, the regions intowhich the surface is divided;

FIG. 5 is another schematic representation in which a treatment liquidis applied onto a curved surface of a member while the number ofapplications is varied from one region to another, the regions intowhich the surface is divided;

FIG. 6 is a schematic illustration of the principle of liquid dischargeby a piezoelectric method;

FIG. 7 shows driving signals applied to a piezoelectric element andwhich include three types for discharging droplets with respectiveminute, middle, and large dot volumes;

FIG. 8 shows another driving signal applied to a piezoelectric elementand which is for discharging a large amount of droplets in per unittime;

FIG. 9 is a schematic representation in which bitmap data are variedfrom one region to another, the regions into which the surface isdivided;

FIG. 10 is a representation of a form of an applicator according toanother embodiment;

FIG. 11 is representation of a liquid discharge head included in theapplicator shown in FIG. 10;

FIG. 12 is a representation of an optical device of the presentinvention applied to glasses;

FIG. 13 is a representation of an optical device of the presentinvention applied to a camera; and

FIG. 14 is a representation of an optical device of the presentinvention applied to a projector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to achieve the foregoing objects, a method of the presentinvention is used for applying a treatment liquid onto a surface of amember. In the method, the treatment liquid is applied in droplet formonto the surface of the member. The surface is divided into a pluralityof regions according to the shape of the surface of the member, and anapplication quantity is controlled for each of the regions.

In an application method according to the present invention, a treatmentliquid is applied in droplet form, and, thus, most of the treatmentliquid is left on the surface of the member as it is. Hence, thetreatment liquid is used with a high efficiency. Also, by controlling anapplication quantity for each of the plurality of regions into which thesurface of the member has been divided according to the shape of thesurface, the difference in film thickness between the upper side andlower side of the surface due to gravity can be reduced.

For example, by setting the application quantity of the treatment liquidfor a region in a higher position in the vertical direction to be largerthan the application quantities for other regions, the difference infilm thickness between the upper side and lower side of the surface canbe reduced, even if part of the treatment liquid runs downward due togravity.

Specifically, if an application surface of the member is in an upwardconvex shape in the vertical direction, the curved surface of the memberis divided into a plurality of substantially concentric regions, and alarger amount of the treatment liquid is applied to regions in the innerside of the plurality of regions than is applied to the regions in theouter side.

If an application surface of the member is in an upward concave shape inthe vertical direction, it is preferable that the curved surface of themember be divided into a plurality of substantially concentric regions,and that the application quantity for a region at a more inner positionbe set larger than the application quantities for the regions at moreouter positions. Thus, the difference in film thickness between theupper side and lower side of the member is reduced in each of the caseswhere the application surface of the member has a convex shape upward inthe vertical direction and where it has a concave shape in the verticaldirection.

In the application method described above, it is preferable that atleast one of the volume or weight per droplet of the liquid and thelanding intervals of droplets is varied so as to control the applicationquantity. Thus, an application quantity of the treatment liquid can becontrolled for each of the plurality of regions into which the surfaceof the member has been divided. Specifically, the application quantityis increased by increasing the volume of the droplets for a region or byreducing the landing intervals of the droplets; in contrast, it isreduced by reducing the weight of the droplets or by increasing thelanding intervals of the droplets. It is also advantageous to repeatapplication of the treatment liquid onto the surface of the member andto set the number of repetitions of application for each of theplurality of regions. Thus, an application quantity of the treatmentliquid can be controlled for each of the plurality of regions into whichthe surface of the member has been divided. Specifically, the number ofrepetitions of applying the treatment liquid is varied, so that theapplication quantity is increased in regions where application isrepeated a large number of times and, in contrast, it is reduced inregions where application is repeated a small number of times.

In order to achieve the foregoing objects, an applicator of the presentinvention is used for applying a treatment liquid onto the surface of amember. The applicator includes a liquid discharge head for dischargingthe treatment liquid in droplet form, and a discharge control device forcontrolling the discharge of droplets from the liquid discharge head.The discharge control device divides the surface of the member into aplurality of regions according to the shape of the surface, and controlsan application quantity for each of the regions.

Since the applicator of the present invention can realize theapplication method of the present invention described above, thetreatment liquid can be used with a high efficiency and thenon-uniformity of film thickness due to gravity can be reduced.Specifically, by applying a treatment liquid in droplet form onto thesurface of a member, most of the treatment liquid that has been appliedonto the surface of the member is left on the surface of the member asit is. Also, by controlling an application quantity for each of theplurality of regions into which the surface of the member is dividedaccording to the shape of the surface, the difference in film thicknessbetween the upper side and lower side of the surface due to gravity canbe reduced.

In the applicator described above, preferably, the discharge controldevice controls the application quantity by varying at least one of thevolume or weight per droplet of the liquid from the liquid dischargehead and the landing intervals of droplets.

Alternatively, the discharge control device may apply the treatmentliquid onto the surface of the member a plurality of times and set anumber of repetitions of application for each of the plurality ofregions.

Thus, an application quantity of the treatment liquid can be controlledeasily for each of the plurality of regions into which the surface ofthe member has been divided.

In order to achieve the foregoing objects, an optical member of thepresent invention has a surface onto which a treatment liquid has beenapplied with the above-described applicator.

An optical device of the present invention includes the above-describedoptical member.

The optical member of the present invention achieves a coating film witha high uniformity and excellent performance and functions.

Also, since the optical device of the present invention includes theabove-described optical member, its optical properties can be enhanced.

Embodiments of the present invention will now be described withreference to the drawings.

Embodiments of the present invention will now be described in detailwith reference to the drawings.

FIG. 1 shows an applicator according to an embodiment of the presentinvention. In FIG. 1, an applicator 10 includes a base 112, a stage 22disposed on the base 112 for supporting a member 20, a first shifter(shifter) 114 between the base 112 and the stage 22 for movablysupporting the stage 22, a liquid discharge head 11 capable ofdischarging a treatment liquid onto the member 20 supported by the stage22, a second shifter 116 for movably supporting the liquid dischargehead 11, and a discharge control device 13 for controlling the operationof discharging droplets from the liquid discharge head 11. Theapplicator 10 also includes an electronic balance (not shown in thefigure) that acts as a weighing instrument, a capping unit 25, and acleaning unit 24, on the base 112. The operations of the applicator 10,including the first shifter 114 and the second shifter 116, arecontrolled by the discharge control device 13.

The first shifter 114 is disposed on the base 112 and is positionedalong the Y direction. The second shifter 116 is fixed to support posts16A that are standing on the base 112 at the backside 12A of the base112. The X direction (second direction), the direction in which thesecond shifter 116 moves, is perpendicular to the Y direction (firstdirection) in which the first shifter 114 moves. The Y direction followsalong the foreside 12B to the backside 12A of the base 112. In contrast,the X direction follows along the transverse direction of the base 112.Each of the directions is in a horizontal plane. The z direction isperpendicular to this plane, and therefore, is perpendicular to the Xand Y directions.

The first shifter 114 is based on, for example, a linear motor, andincludes guide rails 140 A slider 142 is disposed so as to be able toshift along the guide rail 140. To position the slider 142 of the firstlinear-motor shifter 114, the slider 142 is shifted in the Y directionalong the guide rail 140.

The slider 142 has a motor 144 for rotating in a direction (θz) on a Zaxis. The motor 144 may be a direct drive motor, and the rotor of themotor 144 is fixed to the stage 22. Thus, the motor 144, when energized,allows the rotor and the stage 22 to shift together in the θz direction,thereby indexing the stage 22. Hence, the first shifter 114 moves thestage 22 in the Y direction (first direction) and the θz direction.

The stage 22 has a member holder 12 that may shift a member 20 topredetermined positions with the member 20 held in place.

The second shifter 116 is based on a linear motor, and includes supportposts 16A, columns 16B fixed to the respective support posts 16A, aguide rail 62A supported by the columns 16B, and a slider 160 supportedin such a manner as to be able to shift in the X direction along theguide rail 62A. That is, the slider 160 shifts in the X direction alongthe guide rail 62A to be positioned. The liquid discharge head 11 ishung on the slider 160.

The liquid discharge head 11 includes motors 62, 64, 67, and 68 that actas positioning devices in swinging directions. The liquid discharge head11 is vertically shifted along a Z axis by activating the motor 62. TheZ axis extends in the direction (vertical direction) perpendicular to anX axis and a Y axis. The liquid discharge head 11 swings on the Y axisin the β direction by activating the motor 64. The liquid discharge head11 also swings on the X axis in the γ direction by activating the motor67. The liquid discharge head 11 also swings on the Z axis in the αdirection by activating the motor 68. In other words, the second shifter116 supports the liquid discharge head 11 and enables shifting in the Xdirection (first direction) and the Z direction. The second shifter 116also allows movement in the θX direction, θY direction, and θZdirection.

As described above, the liquid discharge head 11 shown in FIG. 1 is ableto shift linearly in the Z axis direction, and to swing in the α, β, andγ directions on the slider 160. As such, the position or orientation ofthe liquid discharge face 11P of the liquid discharge head 11 is able tobe precisely controlled with respect to the member 20 on the stage 22.The liquid discharge head 11 is also provided with a plurality ofnozzles for discharging droplets at the liquid discharge face 11P.

An electronic balance (not shown in the figure) receives an amountequivalent to, for example, 5000 droplets of the liquid from the nozzlesof the liquid discharge head 11 in order to determine and control theweight per droplet of the liquid from the nozzles of the liquiddischarge head 11. The weight per droplet of the liquid is accuratelyobtained by dividing the weight of 5000 droplets measured with theelectronic balance by 5000. The discharge quantity of the droplets fromthe liquid discharge head 11 is suitably controlled according to thisdetermined weight of the droplets.

The cleaning unit 24 cleans the nozzles of the liquid discharge head 11and other parts regularly during device manufacture or during standby,or whenever necessary. The capping unit 25 caps the liquid dischargeface 11P of the liquid discharge head 11 during standby, when devicesare not manufactured, to prevent the liquid discharge face 11P fromdrying.

Since the second shifter 116 shifts the liquid discharge head 11 in theX direction, the liquid discharge head 11 can be selectively positionedover the electronic balance, the cleaning unit 24, or the capping unit25. Hence, by shifting the liquid discharge head 11 to the electronicbalance side, the weight of droplets can be determined even duringdevice manufacture. By shifting the liquid discharge head 11 to abovethe cleaning unit 24, the liquid discharge head 11 can be cleaned. Byshifting the liquid discharge head 11 to above the capping unit 25, theliquid discharge face 11P of the liquid discharge head 11 is capped toprevent drying.

Specifically, the electronic balance, the cleaning unit 24, and thecapping unit 25 are disposed on the backside of the base 112 and underthe shifting path of the liquid discharge head 11, thereby keeping adistance from the stage 22. Since members 20 are fed to and ejected fromthe stage 22 at the foreside of the base 112, these operations are notobstructed by the electronic balance, the cleaning unit 24, and thecapping unit 25.

As shown in FIG. 1, a pre-discharge area (pre-discharge region) 152 ontowhich the liquid discharge head 11 preliminarily discharges droplets ona trial basis (pre-discharge) is provided separate from the cleaningunit 24. The pre-discharge region 152 is on a part of the stage 22 otherthan the region in which the member 20 is supported. Specifically, thepre-discharge area 152 lies along the X direction on the backside of thestage 22, as shown in FIG. 1. The pre-discharge area 152 is secured tothe stage 22, and includes a receiver member having a U shape insection, which is open at upper side, and a replaceable absorptionmember for absorbing discharged droplets put in the U-shaped portion ofthe receiver member.

FIGS. 2(a) and 2(b) are schematic representations of a form of anembodiment of an application method and an applicator according to thepresent invention, and (a) is a side view and (b) is a plan view.

The applicator 10 shown in FIG. 2(a) is used for applying a specifictreatment liquid onto a curved surface 20 a of a member 20, and includesa liquid discharge head 11 for discharging the treatment liquid indroplet form, a member holder 12 for holding the member 20, which is aworkpiece to be subjected to application, and a discharge control device13 for controlling the operation of discharging droplets from the liquiddischarge head 11. FIG. 2 is shown in XYZ rectangular coordinates, inwhich the X axis and the Y axis lie parallel to a horizontal plane andthe Z axis runs perpendicular to the horizontal plane.

In the present embodiment, an optical member 20 is the workpiece to besubjected to application. Exemplary optical members include: opticallenses, such as eyeglass lenses, photochromic lenses, sunglasses, cameralenses, telescope lenses, magnifying lenses, projector lenses, pickuplenses, and microlenses; optical millers; optical filters; prisms;optical members of steppers for semiconductor exposure; and organiccover glasses for portable devices. It should be understood, however,that the member 20 to be subjected to application of the presentinvention is not limited to such optical members, and any type of membermay be used as long as it has a curved surface.

Optical members are often subjected to surface treatments, such as ahard coating and an antireflection treatment, by applying a treatmentliquid onto their surfaces for enhancing their optical performance andfunctions. The treatment liquid applied onto the surfaces of an opticalmember may be part of the raw material of the optical member, the entireraw material of the optical member, part of the raw material of asurface hardening film of the optical member, the entire raw material ofthe surface hardening film of the optical member, part of the rawmaterial of a primer of the optical member, the entire raw material ofthe primer of the optical member, part of the raw material of anantireflection film of the optical member, the entire raw material ofthe antireflection film of the optical member, and so forth.

The raw material composition of the treatment liquid is preparedaccording to the hardening method used. For example, when a raw materialof an optical member; a surface hardening film; a primer; or anantireflection film that is hardened with ultraviolet light, an electronbeam, or a microwave, part of the raw material of the optical member,surface hardening film, primer, or antireflection film may be used whichdoes not contain additives because the hardening reaction proceedswithout these additives. Examples of additives include a reactioninitiator, a catalyst, a solvent, water for allowing a hydrolysisreaction to proceed, and the like. On the other hand, when a rawmaterial of an optical member, a surface hardening film, a primer, or anantireflection film is hardened by heating, the raw material of theoptical member, surface hardening film, primer, or antireflection filmmust contains some additives such as a reaction initiator, a catalyst, asolvent, and water for allowing hydrolysis reaction to proceed. This isbecause the hardening reaction does not proceed unless these additivesare present. Further, a dye and/or a pigment may be added to thetreatment liquid to color.

In the application method of the present embodiment, a hard coat liquid(hard coating composition) of the foregoing treatment liquids is appliedonto the curved surface 20 a of the optical member 20. Specifically,while the optical member 20 and the liquid discharge head 11 are shiftedby the first shifter 114 and the second shifter 116, respectively, thehard coat liquid, being a treatment liquid, is discharged in dropletform from a plurality of nozzles of the liquid discharge head 11 (FIG.2(a)). The application of the droplets is repeated to form a coatingfilm on the curved surface 20 a of the optical member 20. Since thetreatment liquid is applied in droplet form, most of the treatmentliquid applied to the curved surface 20 a of the optical member 20 isleft on the curved surface 20 a as it is. Hence, the treatment liquidcan be efficiently used. In the present embodiment, the convex curvedsurface 20 a of the optical member 20 faces upward, and the hard coatliquid is discharged downward from the liquid discharge head 11 locatedabove the optical member 20. The composition of the hard coat liquidwill be described in detail later.

In the application method of the present embodiment, when the treatmentliquid is applied, the curved surface 20 a of the optical member 20 isdivided into a plurality of regions, and an application quantity of thetreatment liquid is controlled for each of the regions. Specifically,the curved surface 20 a of the optical member 20 is divided into aplurality of concentric regions (here, three regions 40, 41, and 42)around the apex of the optical member 20, as shown in FIG. 2(b). Theapplication quantity (quantity per unit area of the treatment liquid) isincreased at inner regions of the regions 40, 41, and 42 in comparisonwith at outer regions. Hence, in the embodiment shown in FIG. 2(b), theapplication quantity is set to be the smallest in the most outer region40, and is gradually increased inward through the region 41 to theregion 42.

Since the optical member 20 lies such that the curved surface 20 a formsa convex shape upward in the vertical direction, part of the treatmentliquid applied onto the curved surface 20 a moves from the midmostregion on the inner side of the curved surface 20 a to the outer sidedue to gravity. Since the application quantity in inner regions islarger than that in outer regions, the movement of part of the treatmentliquid from the inner side of the curved surface 20 a to the outer sidemakes the quantity per unit area of the treatment liquid uniform at thecurved surface 20 a and, thus, the thickness of the resulting coatingfilm becomes uniform. As such, the application method of the presentembodiment reduces the difference in film thickness between the upperside and lower side of the curved surface 20 a due to gravity.

FIGS. 3(a) and 3(b) show an embodiment in which the treatment liquid isapplied onto the other curved surface of the optical member 20, which isa concave curved surface 20 b and faces upward in the verticaldirection.

In this embodiment, the concave curved surface 20 b of the opticalmember 20 faces upward, and the hard coat liquid is discharged downwardfrom the liquid discharge head 11 located above the optical member 20,as shown in FIG. 3(a).

The concave curved surface 20 b of the optical member 20 is divided intoa plurality of concentric regions (here, three regions 45, 46, and 47)around the undermost point of the optical member 20, as shown in FIG.3(b). The application quantity is increased in outer regions of theplurality of regions 45, 46, and 47 in comparison with in inner regions.Hence, the application quantity is set smallest in the most inner region45, and is gradually increased outward through the region 46 to theregion 47 in that order.

In the present embodiment, since the optical member 20 lies such thatthe curved surface 20 b forms a concave shape upward in the verticaldirection, part of the treatment liquid applied onto the curved surface20 b moves from the outer side of the curved surface 20 b to the midmostregion on the inner side due to gravity. Since the application quantityin outer regions is larger than that in inner regions, the movement ofpart of the treatment liquid from the outer side of the curved surface20 b to the inner side makes the quantity per unit area of the treatmentliquid uniform at the curved surface 20 b and, thus, the thickness ofthe resulting coating film becomes uniform. As such, the applicationmethod of the present embodiment reduces the difference in filmthickness between the upper side and lower side of the curved surface 20b due to gravity, as in the embodiment shown in FIG. 3.

In the embodiments shown in FIGS. 2 and 3, the curved surface of theoptical member is divided into three regions in a concentric manner, butit may also be divided into two regions, or four or more regions.Further, when the curved surface is divided into a plurality of regions,the centers of the regions are not necessarily the same. Also, themanner of division is not always concentric and may be arbitrary.

The division of the curved surface is determined according to the shapeof the curved surface. For example, if the curved surface has a smallcurvature radius, the treatment liquid moves easily at the curvedsurface; therefore, it is advantageous to divide the curved surface intoa larger number of regions. In contrast, if the curved surface of theoptical member is complex, including a convex plane and a concave plane,for example, it is advantageous to divide the curved surface into alarger number of regions according to the shape of the curved surface.

The application quantity for each region is set according to a desiredthickness, the curvature radius and arrangement angle of the curvedsurface, properties of the treatment liquid such as the evaporationspeed, drying conditions, and other factors so that the resulting filmthickness after drying becomes uniform. The application quantity foreach region is controlled by varying the volume or weight of thedroplets discharged from the liquid discharge head, the landingintervals of the droplets, or the number of repetitions of application.An embodiment wherein the number of repetitions of application is variedwill now be described. Another embodiment wherein the volume or weightof the droplets and the landing intervals of the droplets are variedwill be described later.

FIGS. 4 and 5 show embodiments wherein the number of repetitions ofapplication is varied from one region to another. In FIGS. 4 and 5, asin foregoing FIG. 2, the optical member 20 lies such that its curvedsurface 20 a forms a convex shape upward in the vertical direction. Theapplication quantity for inner regions, therefore, has to be increasedin comparison with the application quantity on the outer regions byrepeatedly applying the treatment liquid.

FIG. 4 shows an embodiment in which the area that is subjected torepetitive applications is gradually reduced. First, a treatment liquidis applied over all the regions of the curved surface 20 a of theoptical member 20 that are to be subjected to the application, as shownin FIG. 4(a). In this instance, the application is controlled so thatthe quantity per unit area of the treatment liquid is substantially thesame at the curved surface 20 a. Turning to FIG. 4(b), the treatmentliquid is applied on the more inner areas than the area that has beenpreviously subjected to application. Then, in FIG. 4(c), the treatmentliquid is applied on the more inner areas than the area that has beensubjected to the second application. Through these three applications,the application quantity (allocation) becomes the smallest in the outerregion 40, where the number of applications is the smallest, and theapplication quantity is gradually increased inward through the region 41to the region 42, in that order.

FIG. 5 shows an embodiment in which the area subjected to repetitiveapplication is gradually increased. First, a treatment liquid is appliedonly to the midmost region, of the regions to be subjected toapplication, of the curved surface 20 a of the optical member 20 asshown in FIG. 5(a). In this instance, the application quantity of thetreatment liquid is controlled to be substantially the same per unitarea in this region. Turning to FIG. 5(b), the treatment liquid is thenapplied to regions that define a larger area than that of the regionthat was previously subjected to the application to cover the regionthat was previously subjected to the application. Then, in FIG. 5(c),the treatment liquid is applied to all of the regions to be subjected tothe application so as to cover the regions subjected to the secondapplication. Through these three applications, the application quantitybecomes the smallest in the outer region 40, where the number ofapplications is the smallest, and it is gradually increased inward fromthe region 41 to the region 42 in that order, as in the embodiment shownin FIG. 4. The embodiment shown in FIG. 5 is different from theembodiment shown in FIG. 4 in that the treatment liquid is applied tocover regions previously subjected to the application and, thus, it hasthe advantage of covering steps with the following treatment liquid atthe ends of the regions subjected to the previous application to reducethe step heights.

The number of repetitive applications onto the curved surface of theoptical member is not limited to the three applications as describedabove. That is, the number of applications may be two, or the number ofapplications may be more than four times. Further, when the treatmentliquid is repeatedly applied onto a curved surface, the coating film maybe preliminarily dried after each application, or the applications maybe continuously repeated without drying.

A liquid discharge technique in the applicator of the embodiments willnow be described.

The foregoing liquid discharge head 11 shown in FIG. 2 discharges atreatment liquid in droplet form onto a surface of a member by a liquiddischarge technique, such as ink jetting, to form a coating film.Applicable liquid discharge methods include a piezoelectric method thatuses a piezoelectric element to discharge a treatment liquid, a bubblemethod in which a treatment liquid is bubbled by heating the liquid todischarge the treatment liquid, and other methods known to those skilledin the art. The piezoelectric method among these methods has anadvantage in that it does not affect the material composition becausethe treatment liquid is not heated. In the present embodiment, thepiezoelectric method is used in view of its ability to disperse a widerange of types of treatment liquids, and its controllability withrespect to the droplets.

It should be understood, however, that the method for applying atreatment liquid onto a surface of a member of the present invention isnot limited to the above-described liquid discharge method, and a spraymethod may be used instead. Applicable spray methods include an airatomization method that uses compressed air, and an airless atomizationmethod in which a high pressure is applied to the material to bedischarged from a nozzle tip. A suitable method is selected according tothe viscosity and discharge quantity of the treatment liquid.

FIG. 6 is a schematic illustration of the principle of discharge by apiezoelectric method.

In FIG. 6, a piezoelectric element 32 is disposed adjacent to a liquidchamber 31 (pressure chamber) for accommodating a treatment liquid. Theliquid chamber 31 is connected with a liquid supply system 34 throughwhich the treatment liquid is supplied. The piezoelectric element 32 isconnected with a driving circuit 33 and extends according to a voltageapplied through the driving circuit 33. The extension of thepiezoelectric element 32 deforms the liquid chamber 31 to press thetreatment liquid in the chamber, thereby discharging the treatmentliquid in small droplet form from a nozzle 30.

The liquid discharge head 11 has a plurality of nozzles 30 arranged inline. The discharge control device 13 controls the voltage applied tothe piezoelectric element, that is it controls the driving signals, tocontrol the operation of discharging the treatment liquid from each ofthe plurality of nozzles 30. Specifically, the discharge control device13 varies the volume of droplets, the number per unit time of dischargeddroplets, the intervals between landed droplets (distances betweendroplets), and so forth. For example, the landing intervals of aplurality of droplets can be varied by selecting various nozzles to beused from among the plurality of nozzles arranged in line.

FIG. 7 shows the driving signals applied to the piezoelectric element.The following illustrates the principle of how three different types ofdroplets with respective minute, middle, and large dot volumes aredischarged.

In FIG. 7, driving waveform [A] is a fundamental waveform generated by adriving signal generator circuit. Waveform [B] includes Part 1 of thefundamental waveform and is used for swinging a meniscus (concave orconvex face of the liquid) to diffuse the gummy liquid in the vicinityof the nozzle, thereby preventing a discharge failure of the smalldroplets. B1 represents a state where the meniscus is stable, and B2represents the operation of slightly drawing the meniscus into thenozzle by gently charging the piezoelectric element to increase thevolume of the liquid chamber (pressure chamber). Waveform [C] includesPart 2 of the fundamental waveform and is used for discharging minutedot droplets.

First, the meniscus, in a stable state (C1), is quickly drawn into thenozzle by rapidly charging the piezoelectric element. Then, the volumeof the liquid chamber is slightly reduced (C3) in synchronization withthe timing of beginning a vibration in a direction for filling thenozzle again with the meniscus. Thus, minute dot droplets aredischarged.

The second electric discharge (C4) is used after suspending electricdischarge functions, not only to suppress the residual vibration of themeniscus and piezoelectric element after the operation of dischargingdroplets, but also to control the discharge form of droplets. Waveform[D] includes Part 3 of the fundamental waveform and is used fordischarging middle dot droplets. The meniscus in a stable state (D1) isgently drawn into the nozzle to a large extent (D2). Then, the volume ofthe liquid chamber is rapidly reduced (D3) in synchronization with thetiming at which the meniscus changes the orientation to a direction forfilling the nozzle again with the meniscus. Thus, middle dot dropletsare discharged. The piezoelectric element is charged or discharged tosuppress the residual vibration of the meniscus and piezoelectricelement in D4.

Waveform [E] includes Part 2 and Part 3 of the fundamental waveform andis used for discharging large dot droplets. First, minute dot dropletsare discharged in the process through E1, E2, and E3. A waveform fordischarging middle dot droplets is applied to the piezoelectric elementin synchronization with the timing at which the nozzle is filled withthe liquid due to a slight vibration of the meniscus, remaining afterthe discharge of minute dot droplets. Droplets discharged in a processthrough E4 and E5 has a dot volume larger than that of the middle dotdroplets, and a combination with the foregoing small dot dropletsprovides still larger dot droplets. By controlling the driving signal asabove, three different types of droplets with respective minute, middle,and large dot volumes can be discharged.

FIG. 8 shows driving signal [F] for discharging a large amount ofdroplets for unit time.

In FIG. 8, F1 represents a statically determinate state where a middlevoltage is applied to the piezoelectric element. The meniscus in thisstate is quickly drawn into the nozzle by charging the piezoelectricelement (F2). The piezoelectric element is dynamically extended insynchronization with a timing at which the meniscus vibrates in adirection for filling the nozzle again. The volume of the liquid chamberis reduced following the motion of the piezoelectric element and,consequently, the meniscus is protruded to discharge droplets (F3).Then, recharge is performed (F4) up to a middle potential at the timingof suppressing residual vibration of the meniscus and piezoelectricelement. By repeating vibration and excitation of the meniscus as above,droplets can be discharged in a short cycle.

The landing intervals of droplets may be controlled by varying relativeshifting speeds of the optical member and the liquid discharge headwhile the discharge frequency is set constant, or by varying thedischarge frequency while the relative speeds of the optical member andthe liquid discharge head are set constant.

By reducing the landing intervals of droplets, the discharge density ina specific region increases and the application quantity in the regionincreases. In contrast, by increasing the landing intervals of droplets,the discharge density in a specific region decreases and the applicationquantity of the treatment liquid in the region-decreases. The landingintervals of droplets (discharge density) can be set by changing thebitmap data that designates the landing positions of the droplets.

FIG. 9 shows an embodiment in which the bitmap data is varied from oneregion to another. That is, the regions into which a surface of theoptical member 20 is to be divided. In FIG. 9, the optical member 20lies such that its curved surface 20 a forms a convex shape upward inthe vertical direction, as in FIG. 2. The application quantity for innerregions, therefore, has to be increased in comparison with the outerregions.

In the embodiment shown in FIG. 9, the curved surface 20 a of theoptical member 20 is divided into a plurality of substantiallyconcentric regions (here, three regions 40, 41, and 42) around the apexof the optical member 20. The regions 40, 41, and 42 are each furtherdivided in a grid manner. Thus, a plurality of unit areas (bits), whichdesignate the landing positions of the droplets, are provided. In thepresent embodiment, regions on the inner side of the regions 40, 41, and42 are divided into a larger number of areas than that in regions on theouter side so that the unit areas of the region 42, region 41, andregion 40 increase in size in order (42<41<40). In other words, thedischarge density is set the highest in the midmost region 42, which isdivided into the largest number of areas, and it is gradually reducedoutward through the region 41 to the region 40, in that order. Theapplication quantity (allocation), therefore, becomes highest in themidmost region 42, where the discharge density is set the highest, andit is gradually reduced outward through the region 41 to the region 40,in that order.

The application quantity may be controlled by using one of a number ofapplications, the volume or weight per droplet of the liquid, and thelanding intervals of droplets that have been described above, or byusing a combination of more than one of these factors.

FIG. 10 shows another applicator according to an embodiment, and FIG. 11shows a liquid discharge head included in this applicator.

The applicator includes a liquid discharge head H including a plurality(twelve in this embodiment) of heads H1. At least two of these heads H1simultaneously discharge a treatment liquid, thus putting the treatmentliquid onto a surface of an optical member 20 being a workpiece at onetime (batch drawing).

Specifically, the liquid discharge head H is supported by a supportingmember 1111, a guide rail 113, and the like, in such a manner as to bemovable in the Y-axis direction (secondary scanning direction)designated in the figure. Each head H is supported by the supportingmember 1111 in such a manner to be able to rotate in the θ directiondesignated in the figure. The optical member 20 is supported by a stage1115 that is supported with a guide rail 1116 or the like in such amanner to be able to shift in the X-axis direction (primary scanningdirection) designated in the figure.

In the liquid discharge head H, the plurality of heads H1 (six in aline, twelve in total, in FIG. 11) are arranged in line substantiallyalong the X-axis direction and in two lines at predetermined intervalsalong the Y direction, on a supporting board H7. Each head H1 isdisposed at a predetermined angle with respect to an X axis (or a Yaxis), and the discharge face of the head H1 is provided in line with aplurality of nozzles for discharging liquid.

In the applicator, at least two of the plurality of heads H1simultaneously discharge the treatment liquid to the optical member 20placed on the stage 1115, thus putting the treatment liquid onto asurface of the optical member 20 at one time. In this instance, forexample, while the head H is shifted in the Y-axis direction along theguide rail 1113, the optical member 20 is shifted in the X-axisdirection along the guide rail 1116. The quantities of the treatmentliquid discharged from the nozzles of the respective heads H1 are setregion by region so that desired quantities of the treatment liquid areput onto desired regions of the optical member 20. Since, in theapplicator, the treatment liquid is simultaneously discharged to theoptical member 20 from a plurality of heads H1, the treatment speed canbe increased.

The hard coat liquid (hard coating composition) used in the applicationmethod of the present invention will now be described in terms of itscomposition. As for the solid contents in the hard coating composition,in order to ensure properties sufficient to serve as a hard coatingfilm, the hard coating composition contains a polymerizable organiccompound and inorganic particles as essential ingredients.

The polymerizable organic compound is able to function as a so-calledbinder in the hard coating film. The polymerizable organic compound maybe, for example, an organic silicon compound containing a polymerizablegroup, such as vinyl, allyl, acrylic, methacrylic, epoxy, mercapto,cyano, isocyano, and amino; and a hydrolyzable group, such as alkoxy, inone molecule. By using such an organic silicon compound as thepolymerizable organic compound, a silicone hard coating film can beobtained.

Exemplary organic silicon compounds whose molecule contains apolymerizable group and a hydrolyzable group includevinyltrialkoxysilane, vinyltrichlorosilane,vinyltri(β-methoxy-ethoxy)silane, allyltrialkoxysilane,acryloxypropyltrialkoxysilane, methacryloxypropyltrialkoxysilane,methacryloxypropyldialkoxymethylsilane, mercaptopropyltrialkoxysilane,γ-aminopropyltrialkoxysilane, andN-β(aminoethyl)-γ-aminopropylmethyldialkoxysilane.

The organic silicon compound whose molecule contains an epoxy group anda hydrolyzable group is, preferably, a trialkoxysilane containing amonoepoxy group. Exemplary trialkoxysilanes containing a monoepoxy groupinclude glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane,glycidoxymethyltripropoxysilane, glycidoxymethyltributoxysilane,α-glycidoxyethyltrimethoxysilane, α-glycidoxyethyltriethoxysilane,α-glycidoxyethyltripropoxysilane, α-glycidoxyethyltributoxysilane,β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane,β-glycidoxyethyltripropoxysilane, β-glycidoxyethyltributoxysilane,α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane,α-glycidoxypropyltripropoxysilane, α-glycidoxypropyltributoxysilane,β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane,β-glycidoxypropyltripropoxysilane, β-glycidoxypropyltributoxysilane,γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane,α-glycidoxybutyltrimethoxysilane, α-glycidoxybutyltriethoxysilane,α-glycidoxybutyltripropoxysilane, α-glycidoxybutyltributoxysilane,β-glycidoxybutyltrimethoxysilane, β-glycidoxybutyltriethoxysilane,β-glycidoxybutyltripropoxysilane, β-glycidoxybutyltributoxysilane,γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane,γ-glycidoxybutyltripropoxysilane, γ-glycidoxybutyltributoxysilane,δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyltriethoxysilane,δ-glycidoxybutyltripropoxysilane, δ-glycidoxybutyltributoxysilane,β-methylglycidoxymethyltrimethoxysilane,β-methylglycidoxymethyltriethoxysilane,β-methylglycidoxymethyltripropoxysilane,β-methylglycidoxymethyltributoxysilane,β-methyl-α-glycidoxyethyltrimethoxysilane,β-methyl-α-glycidoxyethyltriethoxysilane,β-methyl-α-glycidoxyethyltripropoxysilane,β-methyl-α-glycidoxyethyltributoxysilane,β-methyl-β-glycidoxyethyltrimethoxysilane,β-methyl-β-glycidoxyethyltriethoxysilane,β-methyl-β-glycidoxyethyltripropoxysilane,β-methyl-β-glycidoxyethyltributoxysilane,β-methyl-α-glycidoxypropyltrimethoxysilane,β-methyl-α-glycidoxypropyltriethoxysilane,β-methyl-α-glycidoxypropyltripropoxysilane,β-methyl-α-glycidoxypropyltributoxysilane,β-methyl-β-glycidoxypropyltrimethoxysilane,β-methyl-β-glycidoxypropyltriethoxysilane,β-methyl-β-glycidoxypropyltripropoxysilane,β-methyl-β-glycidoxypropyltributoxysilane,β-methyl-γ-glycidoxypropyltrimethoxysilane,β-methyl-γ-glycidoxypropyltriethoxysilane,β-methyl-γ-glycidoxypropyltripropoxysilane,β-methyl-γ-glycidoxypropyltributoxysilane,β-methyl-α-glycidoxybutyltrimethoxysilane,β-methyl-α-glycidoxybutyltriethoxysilane,β-methyl-α-glycidoxybutyltripropoxysilane,β-methyl-α-glycidoxybutyltributoxysilane,β-methyl-β-glycidoxybutyltrimethoxysilane,β-methyl-β-glycidoxybutyltriethoxysilane,β-methyl-β-glycidoxybutyltripropoxysilane,β-methyl-β-glycidoxybutyltributoxysilane,β-methyl-γ-glycidoxybutyltrimethoxysilane,β-methyl-γ-glycidoxybutyltriethoxysilane,β-methyl-γ-glycidoxybutyltripropoxysilane,β-methyl-γ-glycidoxybutyltributoxysilane,β-methyl-δ-glycidoxybutyltrimethoxysilane,β-methyl-δ-glycidoxybutyltriethoxysilane, andβ-methyl-δ-glycidoxybutyltripropoxysilane.

In addition, the trialkoxysilanes containing a monoepoxy group include:aliphatic epoxy compounds, such asβ-methyl-δ-glycidoxybutyltributoxysilane; and alicyclic epoxy compounds,such as (3,4-epoxycyclohexyl)methyltrimethoxysilane,(3,4-epoxycyclohexyl)methyltriethoxysilane,(3,4-epoxycyclohexyl)methyltripropoxysilane,(3,4-epoxycyclohexyl)methyltributoxysilane,(3,4-epoxycyclohexyl)ethyltrimethoxysilane,(3,4-epoxycyclohexyl)ethyltriethoxysilane,(3,4-epoxycyclohexyl)ethyltripropoxysilane,(3,4-epoxycyclohexyl)ethyltributoxysilane,(3,4-epoxycyclohexyl)propyltrimethoxysilane,(3,4-epoxycyclohexyl)propyltrimethoxysilane,(3,4-epoxycyclohexyl)propyltriethoxysilane,(3,4-epoxycyclohexyl)propyltripropoxysilane,(3,4-epoxycyclohexyl)prpyltributoxysilane,(3,4-epoxycyclohexyl)butyltrimethoxysilane,(3,4-epoxycyclohexyl)butyltriethoxysilane,(3,4-epoxycyclohexyl)butyltripropoxysilane, and(3,4-epoxycyclohexyl)butyltributoxysilane.

Preferably, the polymerizable organic compound content is in the rangeof 10 to 90 percent by weight, more preferably in the range of 20 to 80percent by weight, and most preferably in the range of 30 to 70 percentby weight, in the solid contents of the hard coating composition. Anexcessively low content may negatively affect the adhesion to a plasticworkpiece that is to be coated, or to an antireflection film that is tobe formed later. Also, an excessively high content may cause theresulting cured film to crack.

The inorganic particles function as a so-called filler of the hardcoating film, and generally have a particle size of about 1 to 100 μm.Specifically, the inorganic particles may be metal oxide particlescontaining at least one metal selected from the group consisting of Si,Sn, Sb, Ce, Zr, and Ti and/or complex particles of metal oxidescontaining at least two metals selected from the group consisting of Si,Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti.

More specifically, the inorganic particles are constituted of particlesof, for example, SiO₂, SnO₂, Sb₂O₅, CeO₂, ZrO₂, or TiO₂ dispersed incolloidal form in a disperse medium, such as water, an alcohol, aCellosolve, and other organic solvents. Alternatively, complex particlescontaining at least two inorganic oxides selected from the groupconsisting of Si, Al, Sn, Sb, Ta, Ce, La, Fe, Zn, W, Zr, In, and Ti maybe dispersed in colloidal form in a disperse medium, such as water, analcohol, a Cellosolve, and other organic solvents.

In addition, in order to enhance the disperse stability of the inorganicparticles in the hard coat liquid, the surfaces of the particles may betreated with an organic silicon compound or an amine compound. Forexample, a monofunctional silane, a trifunctional silane, and atetrafunctional silane may be used as the organic silicon compound forthis surface treatment. On the occasion of the treatment, preferably,the hydrolyzable group is in a state where it has reacted with thehydroxy group of the particles. However, even if part of thehydrolyzable group remains, no problem with stability occurs. Exemplaryamine compounds include ammonium; alkylamines, such as ethylamine,triethylamine, isopropylamine, and n-propylamine; aralkylamines, such asbenzylamine; alicyclic amines, such as piperidine; and alkanolamines,such as monoethanolamine and triethanolamine. Preferably, the content ofthe organic silicon compound or the amine compound contents is about 1to 15 percent by weight to the weight of the inorganic particles.

Preferably, the inorganic particle content in the solid contents of thehard coating composition is about 20 to 80 percent by weight, and morepreferably about 30 to 70 percent by weight. A lower content leads to alower viscosity of the composition, but may not ensure a thicknesssufficient to form a hard coating film. Also, an excessively highcontent may cause the resulting coating film to crack.

For the solvent that is used to dilute the hard coating composition,preferably, water is added to an organic solvent in order to preventclogging in nozzles. The organic solvent improves wettability andadjusts evaporation speed advantageously.

Exemplary organic solvents include: alcohols, such as methanol, ethanol,IPA, and butanol; ketones, such as MEK, 2-pentanone, MIBK, and2-heptanone; esters, such as methyl acetate, ethyl acetate, propylacetate, isopropyl acetate, butyl acetate, isobutyl acetate, sec-butylacetate, isopentyl acetate, methyl propionate, butyl propionate, and3-methoxybutyl acetate; Cellosolves, such as methyl Cellosolve, ethylCellosolve, butyl Cellosolve, isopropyl Cellosolve, propylene glycolmonomethyl ether, and propylene glycol monoethyl ether; and 1,4-dioxane.These compounds may be used singly or in combination of at least twocompounds.

A water-soluble organic solvent with a high boiling point of 200° C. ormore that serves as a liquid wetting agent to prevent clogging may becompounded as the organic solvent. Such water-soluble organic solventsinclude: alcohols with a valence of 2 to 5 that have a carbon number inthe range of 2 to 10 such as ethylene glycol, triethylene glycol, andglycerin; hydrocarbon solvents containing nitrogen, such as formamides,imidazolidinones, pyrrolidone, and amino compounds; and hydrocarbonsolvents containing sulfur. These solvent may be used singly or incombination of at least two solvents.

In order to increase the curing speed of the hard coating composition,disilane may be compounded. A disilane compound is obtained, forexample, by an addition reaction of a dialkyl carbonate withtrichlorosilane, and by subsequent alkoxylation. It can also be obtainedby an addition reaction of a compound having groups capable of additionat both ends and a functional group capable of epoxidation in the insidewith trichlorosilane or the like, and by subsequent alkoxylation.

Since the addition of disilane increases curing speed to shorten curingtime, it advantageously reduces the risk of trapping dust or impuritiesat the application surface during the process step of application ordeposition, therefore improving the yield. Also, the addition ofdisilane advantageously produces the effects of enhancing stainability,reducing the content of a polyfunctional epoxy compound described below,making non-prominent a faulty point with, for example, a surface flaw inthe workpiece.

Preferably, the disilane content is in the range of 3 to 40 percent byweight, and particularly in the range of 5 to 20 percent by weight inthe solid contents. An excessively low content may not produce theeffect of accelerating the reaction, and an excessively high content maydegrade the water resistance of the resulting coating film, or shortenthe pot life of the application liquid.

Preferably, a polyfunctional epoxy compound is added to the hard coatingcomposition to enhance the function of serving as a dye component andincrease water resistance and hot water resistance. The polyfunctionalepoxy compound is widely used as a paint and adhesive, and for casting.Exemplary polyfunctional epoxy compounds include polyolefin epoxy resinsthat are solidified by peroxidation; alicyclic epoxy resins producedfrom cyclopentadiene oxide and cyclohexane oxide, or hexahydrophthalicacid and epichlorohydrin, such as polyglycidyl ester; polyglycidylethers produced from a polyvalent phenol, such as bisphenol A, catechol,or resorcinol, or a polyvalent alcohol, such as (poly) ethylene glycol,(poly) propylene glycol, neopentyl glycol, glycerin, trimethylolpropane,pentaerythritol, diglycerol, or sorbitol, and epichlorohydrin;epoxidized vegetable oil; epoxy novolac produced from a novolac phenolresin and epichlorohydrin; an epoxy resin produced from phenolphthaleinand epichlorohydrin; copolymers of glycidylmethacrylate with a methylmethacrylate-type acrylic monomer or styrene; and epoxy acrylateproduced by a glycidyl ring-opening reaction of the epoxy compoundmentioned above with a (meth)acrylic acid containing monocarboxylicacid.

Furthermore, the polyfunctional epoxy compounds include: aliphatic epoxycompounds, such as 1,6-exanediol diglycidyl ether, ethylene glycoldiglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycoldiglycidyl ether, tetraethylene glycol diglycidyl ether, nonaethyleneglycol diglycidyl ether, propylene glycol diglycidyl ether, dipropyleneglycol diglycidyl ether, tripropylene glycol diglycidyl ether,tetrapropylene glycol diglycidyl ether, nonapropylene glycol diglycidylether, neopentyl glycol diglycidyl ether, diglycidyl ether of neopentylglycol hydroxyhivaline ester, trimethylolpropane diglycidyl ether,trimethylolpropane triglycidyl ether, glycerol diglycidyl ether,glycerol triglycidyl ether, diglycerol tetraglycidyl ether,pentaerythritol diglycidyl ether, pentaerythritol triglycidyl ether,dipentaerythritol tetraglycidyl ether, dipentaerythritol tetraglycidylether, sorbitol tetraglycidyl ether, diglycidyl ether oftris(2-hydroxyethyl)isocyanurate, and triglycidyl ether oftris(2-hydroxyethyl)isocyanurate; and alicyclic epoxy compounds, such asisophorone diol glycidyl ether and bis-2,2-hydroxycyclohexylpropanediglycidyl ether; aromatic epoxy compounds, such as resorcin diglycidylether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether,bisphenol S diglycidyl ether, orthophthalic acid diglycidyl ether,phenol novolac polyglycidyl ether, and cresol novolac polyglycidylether.

Among these compounds, preferable are aliphatic epoxy compounds, such as1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether,trimethylolpropane diglycidyl ether, glycerol diglycidyl ether, glyceroltriglycidyl ether, and triglycidyl ether oftris(2-hydroxyethyl)isocyanurate.

Preferably, the polyfunctional epoxy compound content is in the range of5 to 40 percent by weight, and more preferably in the range of 5 to 20percent by weight, in the solid contents. An excessively low content maylead to an insufficient water resistance of the resulting coating film.Also, an excessively high content may lead to an insufficient adhesionwith an inorganic vapor deposition film when an antireflection film isprovided on the hard coating film.

It is also advantageous to add a tetrafunctional silane compoundexpressed by the general formula Si(OR)₄. Such compounds includetetramethoxysilane, tetraethoxysilane, tetrapropoxysilane,tetraisopropoxysilane, tetrabutoxysilane, tetraphenoxysilane,tetraacetoxysilane, tetraallyloxysilane,tetrakis(2-methoxyethoxy)silane, tetrakis(2-ethylbutoxy)silane, andtetrakis(2-ethylhexyloxy)silane. These compounds may be used singly orin a combination of at least two compounds. Preferably, these compoundsare hydrolyzed in the presence of an acid in an inorganic solvent or anorganic solvent such as an alcohol, before use.

A curing catalyst may be added to the hard coating composition.Exemplary curing catalysts include following groups (1) to (4):

(1) acetylacetonate containing a metal element of Fe (III), Al (III), Sn(IV), and Ti (IV) as the central atom;

(2) magnesium perchlorate and ammonium perchlorate;

(3) saturated and unsaturated carboxylic acids of a fatty acid, aromaticcarboxylic acids, and anhydrides of these acids; and

(4) acetylacetonate containing a metal atom of Li (I), Cu (II), Mn (II),and Mn (III) as the central atom. These may be used singly or in acombination of at least two compounds. In particular, a combination of acuring catalyst in groups (1) to (3) and a curing catalyst in group (4)is preferable from the viewpoint of the increase of pot life.

Preferably, the curing catalyst content is in the range of 0.2 to 10percent by weight in the solid contents of the hard coating composition,and more preferably in the range of 0.5 to 3 percent by weight. Anexcessively low content may not achieve any effect, and a higher contentis uneconomical in some cases because it may not increase curing speed.

The hard coating composition may contain some of the other additivesincluding colorants such as a pigment and a dye, UV absorbents, levelingagents, surfactants, viscosity adjusters, pH adjusters, photochromiccompounds, light and thermal stabilizers such as hindered amines andhindered phenols, antioxidants, and antistatic agents. These ingredientsconstitute the solid contents.

Preferably, the optical member 20 is subjected to surface treatment,such as alkaline treatment, acid treatment, surfactant treatment,polishing using inorganic or organic particles, primer treatment, orplasma treatment, to enhance adhesion before the application of the hardcoat liquid. Also, it is preferable to wash the member 20 with purewater.

The thickness of the hard coating film is preferably in the range of0.05 to 30 μm. An excessively small thickness may not exhibit sufficientfundamental properties, and an excessive large thickness may negativelyaffect the evenness of the surface or cause optical distortion.

After being applied to a workpiece by a liquid discharge method, thehard coating composition is heated at temperatures of 40 to 200° C., andpreferably of 80 to 130° C., for 30 minutes to 8 hours, thus forming ahard coating film on the surface of the workpiece.

Although the above-described composition has thermosetting properties, aUV curable or electron beam curable, polymerizable organic compound maybe used.

Such compounds include photo-curable silicone compositions essentiallycontaining a silicone compound that forms a silanol group by UV exposureand organopolysiloxane having a reaction group that condenses with thesilanol group, such as a halogen atom or an amino group; and UV-curableacrylic monomer composition such as UK-6074 produced by Mitsubishi RayonCo., Ltd.

The resulting hard coating film may be covered with an antireflectionfilm, if necessary. This anti-reflection film can be obtained by vacuumdeposition, ion plating, or sputtering of an inorganic film. In vacuumdeposition, ion beam assisting may be applied in which an ion beam issimultaneously radiated during deposition. The film may be composed of asingle layer or at least two layers.

Inorganic materials used for forming the antireflection film includeSiO₂, SiO, ZrO₂, TiO, Ti₂O₃, Ti₂O₅, Al₂O₃, Ta₂O₅, CeO₂, MgO, Y₂O₃, SnO₂,MgF₂, and WO₃. These inorganic materials may be used singly or in acombination of at least two materials.

At the time of forming the antireflection film, it is preferable thatthe hard coating film is subjected to a surface treatment to enhanceadhesion. This surface treatment is, for example, an acid treatment, analkaline treatment, a UV exposure, a plasma treatment by high frequencydischarge in an atmosphere of argon or oxygen, or an ion beam treatmentusing argon, oxygen, or nitrogen.

FIGS. 12, 13, and 14 are representations of optical devices according toembodiments of the present invention, and respectively show glasses, acamera, and a projector (projection display device).

The glasses 300 shown in FIG. 12, and the camera 310 shown in FIG. 13,respectively, have lenses 301 and 311. The surfaces of the lenses 301and 311 have been coated with a treatment liquid having a predeterminedcapability, such as that of a hard coating, by the forgoing applicationmethod with the foregoing applicator. Since the application of thetreatment liquid by the foregoing application method with the applicatorleads to a high uniformity of the surface coating film for the lenses301 and 311, the glasses 300 and the camera 310 can exhibit excellentoptical properties.

The projector 320 shown in FIG. 12 is a liquid crystal projector usingtransmissive liquid crystal modules as R, G, and B light valves 321R,321G, and 321B. In the projector 320, light emitted from a lamp unit 322using a white light source, such as metal halide lamp, is divided intothree light components R, G, and B respectively corresponding to thethree primary colors R, G, and B (light separating means) by mirrors323, 324, and 325 and dichroic mirrors 326 and 327. The light componentsR, G, and B are transmitted to respective light valves 321R, 321G, and321B (liquid crystal light valves). At this point, light component B istransmitted through a relay lens system including an incident lens 330,a relay lens 331, and an emission lens 332 to prevent optical lossbecause the optical path for light component B is long. After beingmodulated by the light valves 321R, 321G, and 321B, light components R,G, and B corresponding to the respective three primary colors enter adichroic prism 333 (light synthesis means) from three directions to besynthesized again. The synthesized light is projected as a color imageonto a screen 335 through a projection lens 334.

In the projector 320, a treatment liquid having a predeterminedcapability, such as a hard coating, has been applied onto the surfaceof, for example, at least one of the incident lens 330, the relay lens331, the emission lens 332, and the projection lens 334 by the foregoingapplication method with the applicator. Since the application of thetreatment liquid by the foregoing application method with the applicatorleads to a highly uniform surface coating film for the lens, theprojector 320 can exhibit excellent optical properties.

Although the present invention has been described using preferredembodiments with reference to the accompanying drawings, as above, itgoes without saying that the present invention is not limited to theforms of the embodiments. The above-described shapes and combinations ofcomponents are just examples, and various modifications may be madeaccording to design requirements and the like without departing from thespirit and scope of the invention.

In the application method and the applicator of the present invention,by controlling an application quantity for each of the plurality ofregions into which the surface of the member is divided, according tothe shape of the surface, the difference in film thickness between theupper side and lower side of a curved surface due to gravity can bereduced to form a uniform coating film over the curved surface.

Also, by applying a treatment liquid in droplet form onto the curvedsurface, the efficiency in use of the treatment liquid can be increased.

Furthermore, by using the optical member of the present invention, theresulting coating film can exhibit excellent characteristic propertiesand functions because of a high uniformity of the film.

In addition, since the optical device of the present invention includesthe above-described optical member, its optical properties can beenhanced.

1. An applicator for applying a treatment liquid onto a surface of a member, comprising: a liquid discharge head for discharging the treatment liquid in droplet form; and a discharge control device for control the discharge of droplets from the liquid discharge head, wherein the discharge control device divides the surface of the member into a plurality of regions according to the shape of the surface, and controls the application quantity for each region.
 2. An applicator according to claim 1, wherein the discharge control device controls the application quantity by varying at least one of the volume or weight per droplet of the liquid from the liquid discharge head and the landing intervals of droplets.
 3. An application method according to claim 1 or 2, wherein the treatment liquid is repeatedly applied by the discharge control device onto the surface of the member a plurality of times, and a number of repetitions of application is set for each of the plurality of regions.
 4. An optical member having a surface onto which a treatment liquid has been applied with an applicator as set forth in claims 1 or
 2. 5. An optical device including the optical member as set forth in claim
 4. 